The central premise underlying the San Antonio Nathan Shock Aging Center described in this proposal is that identifying the biological mechanisms that lead to senescence can best be achieved by manipulating the whole organism genetically, nutritionally, or pharmacologically in ways that modify the aging process rather than by relying on phenomenological studies. Our Center will focus its effort on providing investigators with "state-of-the-art" scientific infrastructure, resources, and services that can be used in the development and use of rodent models to study pertinent questions on the basic biology of aging. The Center proposed in this application will consist of five Resource Cores (a Transgenic Core, an Animal Core, a Pathology Core, a Proteomics/Oxidative Stress Core, and an Optical Imaging Core) and a Research Development Core that will provide investigators with resources/services in four areas. First, the Transgenic and Animal Cores will generate novel rodent models for Center faculty members by genetic procedures or nutritional and pharmacological manipulations. Second, the Animal, Pathology, Proteomics/Oxidative Stress, and Optical Imaging Cores will provide Center faculty members with the resources/services required to characterize the effect of the various manipulations on aging in rodents. Third, the Research Development Core will provide investigators new to aging research with pilot grants and mentors to develop research programs in aging that are competitive in acquiring extramural funding.